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Subject: Re: Mathematical impossibilities regarding Deep Blue statements by Bob

Author: David Rasmussen

Date: 11:25:18 01/30/02

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On January 30, 2002 at 14:15:32, Dann Corbit wrote:

>On January 30, 2002 at 14:00:32, David Rasmussen wrote:
>
>>On January 30, 2002 at 09:43:49, Vincent Diepeveen wrote:
>>
>>I don't know anything about what Bob has stated, but I agree that 18 ply
>>fullwidth was/is impossible, even with 200 Mn/s.
>>
>>Please email me how you do singular extensions, Vincent. :)
>
>I've done 18 ply searches with a PC.  What makes you think it is impossible for
>a machine that can peak at one billion nodes per second?
>
>They did not use null move, but neither did they blindly search the whole tree.

It is of course possible to search 18 ply. Chezzz searches 35 ply in fine70 in 1
second :)

But in a normal middlegame situation with a high branching factor, I don't
believe it, even if you have 200 Mn/s. As far as I understood, DB _did_ pretty
much blindly search "the whole" (of course they used alpha-beta pruning) tree.
They had extensions, but as far as I know, no forward pruning of any kind. I
might be wrong.

/David



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